We are in San Miniato al Tedesco in the Grand Dukedom of Tuscany and it is November 1594. Monna Gostanza da Libbiano is a sixty-year old peasant woman who works as a midwife and weaver. She is also known as a powerful healer and this comes to the attention of the ecclesiastic authorities that put her on trial for witchcraft. Two inquisitors, Fathers Tommaso Roffia and Mario Porcacchi interrogate her in an attempt to make her confess her dark deeds. Gostanza soon tires of affirming her innocence and enters instead into the personality of a witch and invents fantasies like sexual relations with animals and the Devil that play heavily to popular beliefs of the time. The woman is so clever that she fools the two priests into believing her every word and readies herself to face death when unexpectedly Father Dionigi Costacciaro, the old and extremely powerful Grand Inquisitor of Florence comes to listen to Gostanza’s stories…